Technical Field of the Invention
The present invention relates to communicating at long distances using lasers, and more particularly to using a telecentric lens and lasers for space based communication.
Description of the Prior Art
Modulating Retro-Reflectors are described in Salas et al, IAC-12.B4, 6B, 11, in which a high powered laser interrogator beam is directed from the ground to a satellite. Within the satellite, the beam is redirected back to ground using a corner cube reflector. On the satellite, the beam passes through multiple quantum well modulators, which can admit or block passage of the beam to encode a data signal onto the returning beam.
A similar system is described in U.S. Patent Publication 2007/0297805 to Rabinovich et al.
Integration of VCSEL lasers with photodetectors is described in Giannopoulos, et al., Two-dimensional integration of a vertical-cavity surface-emitting laser and photodetectors for position sensing, Applied Optics, Vol. 47, No. 25, September 2008, pp 4555-4559. A VCSEL is positioned in the center of a position sensor, and has photodetectors positioned about the VCSEL.